Prosthetically, anterior and one posterior side implants can be splinted for a fixed prosthesis.
The other posterior segment is restored independently with a three-unit fixed prosthesis.
Three implants are used for the smaller segment (first premolar, second premolar, and molar).
This compensates for force factors and alignment, as they are almost in a straight line.
At least six implants are used, often seven, to ensure the smaller segment has three implants.
The primary advantage is the elimination of cantilevers, reducing the risk of occlusal overload.
Another advantage is having two segments instead of one.
The larger segment (molar to contralateral canine) has implants in three to four horizontal planes.
No cantilever means less damaging forces are applied.
If repair is needed, the affected segment can be removed more easily.
Posterior disclusion in excursions limits lateral loads, especially on prostheses with fewer implants.
Disadvantages include needing abundant bone in both posterior regions and additional costs for implants.
Some modifications include fabricating three independent prostheses: four to five implants in the anterior, two in the first molar sites, two in the first premolar sites, and two in the canine regions.
Secondary positions are the two second premolar and central incisor (midline) sites.
Posterior restorations extend from the first molar to the first premolar; an anterior restoration replaces the six anterior teeth.
Advantages of smaller segments are individual restorations and flexibility/torsion of the mandible.
The primary disadvantage includes the greater number of implants required in severe force scenarios.
Nine implants are rarely needed, regardless of bone density/force factors.
Treatment Option 5: All-on-Four Protocol.
was developed to avoid regenerative procedures, treatment costs, and patient morbidity.
developed by Malo, uses four anterior implants in the edentulous jaw to support a provisional, fixed, and immediately loaded prosthesis.
Most commonly, two anterior implants are placed axially, while two posterior implants are placed at an angle (approximately 45 degrees).
This increases A-P spread and decreases cantilever length.
Tilted implants generate favorable biomechanical outcomes and have high survival rates with low complications.
The tilted implants allow for longer implants, reduce cantilever length, and avoid vital structures like the inferior alveolar canal.
it is popular due to the decreased treatment costs and treatment duration.
Most dental implant has survival rates of 98%.
However, all-on-four protocols require additional surgical/prosthetic skills; clinicians on their learning curve should be cautious.
Advantages of unilateral cantilever and increased anteroposterior spread, with adequate posterior bone for high force factors and square arch forms.
Treatment option 4 has high support without a cantilever, increasing the anteroposterior spread.
Advantages included no cantilever, increased anteroposterior spread, and highest support with bilateral posterior bone for poor bone density.
Disadvantages: More implants required and bilateral posterior bone.
High survival requires clinicians to have additional surgical/prosthetic skills or augmentation could take place upon failure of the prosthesis.